Hildegard Katarina Thorell, née Bergendal was a Swedish painter.

Thorell was born in Kroppa parish, Värmland County, Sweden. She the daughter of August Filip Bergendahl and Hildegard Wennerlund. In 1872 she married to the auditor Oskar Reinhold Thorell. She studied at the Royal Swedish Academy of Fine Arts in Stockholm from 1876 to 1879, where she was the only married female student. She became an agré at the Royal Swedish Academy of Fine Arts in 1883 and was apprenticed to Bertha Wegmann. Later she travelled to Paris, where she studied with Léon Bonnat and Jean-Léon Gérôme.

Thorell mainly painted large portraits, for example Modersglädje (1894), Portrait of a Distinguished Young Lady (1880), Portrait of a Young Girl (1916), Painting of Fanny Brate (1918) and Young woman with fan (1893).